1. Technical Field of the Invention
The present invention relates to a mesoporous silica utilizing the structure of a self-assembled anionic surfactant as the template, characterized by using a basic silane, and a process for producing the same.
2. Related Art
Mesoporous silicas such as MCM-41, wherein surfactant micelle has been utilized as the template, have high specific surface area and uniform pore size, and they have been applied in various fields because of their structural features. Methods for synthesizing the mesoporous silicas utilizing cationic or nonionic surfactants as templates have been well established (JP-A-2001-261326).
Anionic surfactants are higher in versatility and advantageous in costs and diversity as compared with the other three types of surfactants, i.e., cationic, nonionic and amphoteric surfactants. Although it has been reported that anionic surfactants can be used as a template in the same manner as for the other three types of surfactants to produce mesoporous metal oxides of iron, nickel, cobalt, etc. with three-dimensionally unstable, lamellar, mesoporous structures (Takashi Tatsumi, et al, Materials Integration, P. 50, Vol. 13, No. 10 (2000), and Q. Huo, G. D. Stucky, et al, Chem. Mater., 1994, 6, 1176-1191), mesoporous silicas using the anionic surfactant templates have not been reported. Thus, the mesoporous silicas could not be synthesized using anionic surfactants practically. The reason therefor seems because silicate monomers have little affinity for the anionic surfactants, whereby the silicate monomers are polymerized not on the boundary surface of the micelle or self-assembly of the anionic surfactants but in solvent bulk under alkaline conditions. The thus-produced silicate has an amorphous structure similar to the polymerizate under alkaline conditions without surfactants.